Put the lemon slices in a large bowl and pour the brandy over them. Let macerate at room temperature overnight.
In a small saucepan, combine the sugar with 3/4 cup water and bring to a boil over high heat. Cook, stirring occasionally, until the sugar dissolves, 2 to 3 minutes. Remove from the heat, add the tea bags, and steep for 2 to 3 minutes. Discard the tea bags and let the syrup cool.
At least 3 hours and up to 6 hours before serving, combine the lemons, brandy, syrup, rum, and pineapple in a large pitcher or bowl. Chill in the refrigerator.
Just before serving, pour the punch into a large chilled punch bowl with a block of ice. Add the sparkling wine and sparkling water, and gently stir.